Backing up a Linux VM

My company just installed a BUE 3600 appliance. We have began using it to backup our VM environment on one server, but we have another server that has a Linux OS running our wordpress blog. When we try to back it up we get this error.

The job failed with the following error: Unable to create a snapshot of the virtual machine. The virtual machine may be too busy to quiesce to take the snapshot.

Do we need a Linux client for the server? Or is this error caused by something else?

No Linux agent is required to perform virtual machine backup of Linux server as for Linux VM backup GRT is not an option as like in for windows virtual machine backup it support GRT and Application GRT too and particularly doing application GRT backup of virtual machine ,remote agent is required to be installed on windows virtual machine but for Linux virtual machine this is not needed as GRT backup are not supported and not possible.

Please ensure the Linux version on the virtual machine is supported version by backup exec running on 3600 appliance